Creutzfeldt-Jakob
Disease
Introduction
Alzheimer's disease is the most common of a large group of disorders known as "dementias." It is an irreversible disease of the brain in which the progressive degeneration of brain cells causes thinking ability and memory to deteriorate. Alzheimer's disease also affects behaviour, mood and emotions, and the ability to perform daily living activities.
There is currently no cure for Alzheimer's disease, but there are treatment options and lifestyle choices that can slow its progression and, within the next five years, treatments are expected that may well stop the disease in its tracks! Also, the pursuit of new research strategies should one day help restore some lost function and memory.
Alzheimer's disease progresses through early, middle and late stages before reaching the final end of life stage. However, identifying the transition from one stage to another is often difficult. Not only does the disease usually progress slowly, but the symptoms related to each stage tend to overlap and the order in which they appear and how long they last varies from person to person.
The duration following diagnosis is usually seven to ten years. However, when the diagnosis is delayed, as it may be if the affected person fails to see a doctor early on, the disease duration is shorter than this. Conversely, as the ability to diagnose Alzheimer's disease improves and people become more willing to be assessed, survival times following diagnosis are lengthening.
"Related dementias" resemble Alzheimer's disease in that they also involve a progressive degeneration of brain cells that is currently irreversible. They include the dementia associated with Vascular Dementia (the second most common dementia after Alzheimer's disease), Frontotemporal Dementia, Creutzfeldt-Jakob Disease, Lewy body Dementia, Parkinson's disease, and Huntington disease.
Sometimes a person may have a relatively rapid development of symptoms such as mood swings, memory loss, behaviour changes, or difficulties with speech and movement. This may suggest a dementia other than Alzheimer's disease, in particular, Creutzfeldt-Jakob Disease (CJD). In any event a person should always seek a thorough medical assessment if any of these symptoms are present.
Regardless of the type of dementia, individuals are encouraged to obtain information and support from the Alzheimer Society.
What is Creutzfeldt-Jakob Disease?
Creutzfeldt-Jakob Disease (CJD) is a rare, rapidly developing and fatal form of dementia caused by infectious proteins called prions. Prions are proteins that occur naturally in the brain and are normally harmless. When they are misshapen, however, they can have devastating effects, attacking the brain, killing cells and creating gaps in tissue.
Prion diseases affect both humans and animals. Prion diseases started to attract public attention during the mid 1980s with the bovine spongiform encephalopathy (BSE) epidemic, a prion disease of cattle. The best known prion disease in humans is Creutzfeldt-Jakob Disease. It affects about one to two persons in a million worldwide each year, with about 35 new cases being diagnosed in Canada every year.1
There are two types of CJD: classic CJD and variant CJD (vCJD). The three types of classic CJD include:
- Sporadic: This type of CJD accounts for 90% of cases in Canada. It affects people between 45-75 years old. The cause is unknown and the disease appears without warning. Most persons with sporadic CJD die within one year.
- Familial or genetic: This type of CJD appears in families with an abnormal gene. It accounts for 7% of cases. Genetic testing can be done by a blood test or brain tissue examination after death. A person who has this abnormal gene has a 50% chance of passing it on to each of his or her children. Gerstmann-Sträussler-Scheinker (GSS) and Fatal Familial Insomnia (FFI) are very rare forms of genetic CJD.
- Iatrogenic : Few persons around the world get CJD from accidental transmission during a medical procedure such as: human pituitary hormone therapy, human dura-mater grafts, corneal grafts or instruments used in neurosurgery. Less than 1% of people have this type of CJD.
Variant CJD affects younger people at an average age of 28 years. This form of CJD is related to eating beef infected with bovine spongiform encephalopathy (BSE) or, as it is commonly called, "mad cow disease". Also, variant CJD has recently been reported to be transmitted by a blood transfusion from a person with variant CJD in the United-Kingdom.2
How does Creutzfeldt-Jakob Disease affect the person?
Classic CJD can mimic many other dementias. It has a rapid onset and decline in thinking ability once symptoms appear.
The person may have:
- mood swings
- memory problems
- a lack of interest and not act like him or herself
- rapidly progressing dementia with a loss of memory and thinking abilities
- difficulty with balance when walking
- clumsiness
- vision problems, including blindness
- stiff limbs
- muscle jerks or twitching
- difficulty with speech
- difficulty swallowing
Discomfort
Neurological examination of people in the later stages of CJD indicate that they lose awareness of their condition as the disease progresses. In the early stages, however, persons with CJD can develop marked fear, which can be very distressing and is probably associated with visual hallucinations. They may feel discomfort; some of the symptoms of the disease - such as myoclonus (sudden jerking of the limbs) are distressing for caregivers to witness. There are medications and care strategies which can relieve these symptoms and make the person more comfortable. For more information on the care of a person with CJD, visit the CJD Foundation website at www.CJDfoundation.org.
Coma and death
People with sporadic CJD generally live less than 12 months after the signs and symptoms appear, although some people may live as long as two years. Most people lapse into coma before death. Death is usually a result of complications such as heart failure, respiratory failure or pneumonia.
Variant CJD affects younger persons with an average age being 28. Symptoms of variant CJD are:
- depression, withdrawal and behaviour changes
- pain and odd sensations in the face or limbs
- difficulty walking
- progressive dementia
- inability to move or speak
People with variant CJD tend to live slightly longer – about 12 to 14 months after signs and symptoms appear.
How is Creutzfeldt-Jakob Disease assessed?
Creutzfeldt-Jakob Disease is very difficult to diagnose, especially in the beginning of the disease. There is no test to diagnose CJD in a living person. The only way to confirm if a person has CJD is to examine brain tissue after death during an autopsy. However, doctors will do a detailed exam and many tests to help diagnose this disease. The following steps may be taken:
- Detailed medical history: This will help the doctor learn when the person's signs and symptoms started, as the length of CJD is of a short duration
- CT scan (computerized tomography) produces a picture of the brain. It can be used to diagnose other diseases, as well.
- MRI (magnetic resonance imaging): An MRI also produces a picture of the brain. It helps to distinguish sporadic CJD from variant CJD. It can also be used to find other diseases.
- EEG (electroencephalogram) measures the electrical activity of the brain. Sometimes, but not always, there is a specific pattern on the EEG that helps to diagnose CJD.
- Lumbar puncture: Fluid can be taken from the person's spine and examined to exclude other infections of the brain. One of the tests is called the 14-3-3 protein. If the 14-3-3 is positive it means that there has been some brain cell death but not necessarily due to CJD.
- Blood test: A blood test is sometimes done to rule out other diseases and to determine the possibility of the genetic form of CJD. For a list of genetic counsellors in Canada please go to the Canadian Association of Genetic Counsellors website: www.cagc-accg.ca.
- Brain autopsy: The only way to confirm CJD is by looking at brain tissue with a microscope after death. Brain autopsies are performed only in certain large hospitals in Canada. The CJD Surveillance System (see contact information at end of this sheet) can help make arrangements for a brain autopsy if CJD is suspected and if the next of kin gives their consent.
What are the risk factors for Creutzfeldt-Jakob Disease?
The true risk of developing either form of CJD is largely unknown. At this time, there is no specific way to protect a person from getting sporadic or familial CJD. However, certain factors may increase one's risk:
Pituitary hormone treatment: If pituitary hormone treatment derived from human tissue was used prior to the genetically engineered form of the hormone becoming available in the 1980s, there is an increased risk. Since 1985, human growth hormones are made synthetically and, as a result, there is no longer any risk of transmission from this source.
Family history of CJD: A few people have a genetic mutation that increases their likelihood of developing the disease. A blood test or brain tissue examination after death can be done to find out if a person has the mutation.
Contaminated surgical instruments: A few people have been infected from contaminated instruments used during brain surgery. Today, instruments used on the brain of someone with possible CJD are destroyed.
CJD precautions: These are infection control precautions required only for certain medical procedures involving specific tissue. When embalming the remains of a person who has died of a possible prion disease, the World Health Organization and the Public Health Agency of Canada recommend that funeral workers use CJD precautions.
You cannot catch CJD by touching, feeding or taking care of a person with CJD at home. CJD is not a contagious disease transmitted by social or sexual contact, or by air. Since other infections can be spread that way, it is recommended that the following basic precautions be followed:
- Wash your hands before eating or drinking
- Protect your hands and face from exposure to the affected person's blood or body fluids
- Cover cuts or wounds with water-proof bandages
Blood transfusions: The Canadian Blood Services and Héma-Québec screen and exclude persons with CJD from giving blood.
For variant CJD only: Eating beef from countries with a relatively high rate of transmissible spongiform encephalopathy (TSE) may increase risk. To help reduce the risk of contracting CJD from infected beef consider the following options: be selective when eating beef in parts of the world where less stringent safeguards may exist; avoid eating the highest risk parts of cattle, such as eyes, brain, spinal cord and intestines.
Is there treatment?
At present, there is no known cure for CJD and no effective way to slow its progression. It is important to relieve pain, discomfort and other symptoms such as jerking movements and unsteadiness. Supportive nursing care is focused on keeping the person as comfortable as possible.
For more information
Contact your local Alzheimer Society.
More information can be obtained from the following:
- The Public Health Agency of Canada's Creutzfeldt-Jakob Disease Surveillance System (CJDSS) study team. The Public Health Agency of Canada CJD Surveillance System conducts active monitoring of CJD in Canada. Their main purpose is to study human prion diseases in Canada and to protect public health by reducing the risk of transmitting prions. The CJD Surveillance System has a 24 hour service to make arrangement for brain autopsies of persons suspected of having CJD. More information about the CJD Surveillance System can be found on the website: www.phac-aspc.gc.ca/hcai-iamss/cjd-mcj/cjdss-eng.php or call: toll free 1-888-489-2999
- Canadian Food Inspection Agency, BSE Fact Sheet or website.
- Prionet Canada
- CJD Foundation (US) or toll free: 1-800-659-1991.
- CJD Support Network (UK)
- CJD Support Network (Australia)
- European Collaborative Study Group of CJD (EuroCJD)
- University of California, San Francisco
- Healthy Ontario (Ministry of Health and Long Term Care, Ontario)
- Canadian Association of Genetic Counsellors
- World Health Organization (WHO): WHO infection control guidelines for transmissible spongiform encephalopathies. Report of a WHO consultation, Geneva, Switzerland, 23-26 March 1999. Geneva, World Health Organization, 2000.
Footnotes:
- Public Health Agency of Canada (2007). CJD and human prion diseases.
- Brown, P. (2007). Creutzfeldt-Jakob disease: reflections on the risk of blood product therapy. Haemophilia, 13, 5. p. 33-40.
[The contents of this document are provided for information purposes only, and do not represent advice, an endorsement or a recommendation, with respect to any product, service or enterprise, and/or the claims and properties thereof, by the Alzheimer Society of Canada. The Information Sheet is not intended to replace clinical diagnosis by a health professional.]
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